Assessing potential financial and environmental benefits of Brick-to-Brick manufacturing

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International HISER Conference on Advances in Recycling and Management of Construction and Demolition Waste

21-23 June 2017, Delft University of Technology, Delft, The Netherlands

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Assessing potential financial and environmental benefits of Brick-to-Brick manufacturing

Wim Debacker1, Sofie De Regel1, Omar Amara1, Wai Chung Lam1, Jef Bergemans2, Kris Broos2 and Dirk Van Wouwe3

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VITO, Smart Energy and Built Environment, Thor Park 831, 3600 Genk, Belgium, Phone (+32) 14 33 58 94; E-mail: wim.debacker@vito.be

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VITO, Sustainable Materials, Boeretang 200, 2800 Mol, Belgium 3

Dumoulin Bricks, Moorseelsesteenweg 239, 8800 Roeselare, Belgium Abstract

Due to a lack of high value applications for masonry debris, there is currently no incentive to separate it from other stony fractions.

Within this paper the potential environmental and financial advantages and drawbacks related to the production of 1 ton of load-bearing clay bricks with a compressive strength of 15MPa, in which the coarsening agent is substituted by masonry debris aggregates (cf. brick-to-brick manufacturing) are investigated. Life cycle assessment and life cycle costing analysis were used to calculate environmental impact and financial costs, respectively.

Compared to the business-as-usual practice, "brick-to-brick" manufacturing leads to a decrease in potential impact related to some environmental impact categories (2-6%) and a decrease of 10% of operational costs related to acquisition and transport of main resources to the production facilities. Nevertheless, the environmental impact and operational costs related to the consumption of electricity from the grid and natural gas during the manufacturing process surpass the potential benefits related to the substitution of the coarsening agent. In order to further improve the environmental and financial profile of brick production processes at Dumoulin Bricks facilities, combined measures to decrease energy consumption and substitution of primary resources need to be investigated further.

Keywords: masonry debris, LCA, LCCA, brick production, hotspot analysis.

Introduction

In Belgium more masonry debris comes out from selective demolition of buildings than bricks are produced on a yearly basis. In 2013, less than 1785 kton of bricks were produced for the Belgian market, but circa 2250 kton of masonry debris was generated in Flanders alone [1, 2]. Due to the lack of demand of masonry debris aggregates for new applications, there is currently little to no (economic) incentive for demolition companies to separate masonry debris on-site from other stony fractions.

Within the HISER project, new ways to recycle typical demolition waste fractions, such as masonry debris, are currently investigated, tested and demonstrated, in order to stimulate market uptake of new applications. In order to select sound recycling alternatives, the environmental and financial characteristics of innovative recycling technologies are assessed and compared with a business-as-usual (BaU) situation. Within this paper screening results are discussed of a comparative environmental and financial assessment of (1) a BaU brick manufacturing within the Dumoulin Bricks facilities in 2015, using an opening agent (i.e. coarse grained material to reduce drying shrinkage) made of primary resources (i.e. porphyry sand) and (2) a virtual brick-to-brick manufacturing within the same facilities in 2015, using masonry aggregates from demolition waste as an opening agent.

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231 Methodology

To assess and compare environmental and financial characteristics of both brick manufacturing solutions, life cycle assessment (LCA) and life cycle costing analysis (LCCA) have been used. Within the environmental assessment fourteen impact categories are calculated, according to the European PEF Guide [3]. The Belgian environmental assessment method MMG [4] is used within sensitivity analyses. Within the economic assessment, financial costs are divided into two major groups: capital expenditures (CAPEX) and operational costs (OPEX). For both comparative assessment studies the same functional unit has been used: i.e. the production, packaging, transport to the building site of 1 ton of conventional (perforated load-bearing) clay brick with a compression strength of 15MPa and using Ypresian clay, produced by Dumoulin Bricks for the Belgian market in 2015. System boundaries for the brick-to-brick solution are shown in the block flow diagram in Figure 18.

Figure 18. Block flow diagram of the virtual brick-to-brick manufacturing case Results

Hotspot Analyses. From a financial point of view, all costs related to the acquisition of

material resources (cf. module A1 in Figure 18) remain the same compared to the BaU brick manufacturing case, with the exception of the acquisition of the opening agent. We assumed in this virtual case that there is enough supply of masonry debris in the neighbourhood of the Dumoulin production facilities to be used as an opening agent. As there is a demand for it (i.e. by at least Dumoulin), we assumed that demolition companies will be willingly to sort the masonry fraction (separately) on-site, as long as the cost to deliver it to the crushing company is less than for delivery of mixed stony fraction. Based on expert judgment and a

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restricted market analysis we estimated the cost for the brick manufacturer (without transport) – in relation to the used functional unit – at 0,5676 euro for 1 ton of produced bricks.

Where in the BaU brick manufacturing case the extraction of porphyry sand had a significant effect on "water resource depletion" and "land use", this is no longer true for its substitution by masonry debris aggregates. The recuperation of crushed and sieved masonry debris is relevant for all impact categories, but doesn't play an important role in any of them; the (combined) relative share of these processes is less than 15% for all categories.

Even though the environmental impacts and the financial costs related to the production of recycled opening agent are lower than the substituted porphyry sand, the impacts of both processes do not represent a major part of the environmental and financial burdens over the entire production bricks process (including the supply of bricks to the construction site). The manufacturing process (cf. module A3 in Figure 18) within the BaU and brick-to-brick production cases dominates the environmental burdens in each impact category, mainly because of the electricity and natural gas used in the manufacturing process, as well as the emissions generated by the production of bricks. We have assumed that the energy consumption within the manufacturing process and related emissions remains the same in both cases. The manufacturing stage is also the most relevant life cycle stage in terms of financial costs, mainly due to the costs related to energy, infrastructure and personnel.

The transport stages (modules A2 and A4 in Figure 18) are relevant, but not as important as the manufacturing stage. Both transport stages have a major contribution to the impact category "mineral, fossil and renewable resource depletion" and operational costs related to fuel and personnel.

Comparative assessment. Looking at the absolute characterisation results, the brick-to-brick

manufacturing case is from an environmental point of view preferred above the BaU brick manufacturing case for all impact categories. Nevertheless, relative differences for almost all categories are equal or smaller than 1%. These relative results are, accordingly, too small to make hard conclusions. Exceptions are "land use" (6%), "water resource depletion" (5%) and "mineral, fossil and renewable resource depletion" (2%), where there is a more distinct preference for the brick-to-brick manufacturing case. Similar conclusions can be drawn, when both cases are compared based on the MMG impact assessment methods.

Also from a financial perspective, the relative difference between the BaU and brick-to-brick manufacturing is too small (i.e. 1%) to conclude that the latter one receives the benefit. Although the combined operational costs related to the acquisition and transport of resources to the production facilities is lowered by 10%, the biggest expenses are still attributed to the manufacturing stage. This stage is characterised by high operational energy costs, personnel costs, and investment and maintenance costs related to the equipment and site. Substitution of porphyry sand by masonry debris aggregates will not lower these manufacturing costs.

Improvement steps. Based on the above, we can conclude that, in addition of the

replacement of the opening agent, the following measures should be investigated in order to reduce the environmental and economic burden related to the brick manufacturing (at the Dumoulin Bricks facilities):

• (partial) substitution of coal shale sand, by masonry debris aggregates (or other to be investigated local alternatives), with a special focus on possible trade-offs regarding energy consumption and emissions during the manufacturing stage.

• different ways to decrease the consumption of electricity from the grid, e.g. by use of local renewable energy sources, and natural gas for heat, e.g. by (better) using excess heat within the firing kiln within other production processes.

This figure results from the multiplication of the fraction of the opening agent needed for the production of 1 ton of bricks and the price of crushed and sieved masonry debris from a crushing company.

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• investing in own crushing and sieving equipment at the production facilities and starting a collection initiative to have a direct supply of masonry debris aggregates.

• selection of alternative transport modes and/or fuel choice(s) to transport resources to and from the factory, e.g. through barge.

Conclusion

Although the absolute impact results and calculated costs within the conducted analyses suggest that the substitution of opening agent(s) by masonry debris aggregates within brick manufacturing, will probably lead to environmental and financial improvements compared to the business as usual practice, it is imperative to take into account combined measures to decrease energy consumption and substitution of primary resources, in order to take (more) important steps in enhancing the environmental and financial profile of the systems under study.

Acknowledgement

This research is part of the HISER project (www.hiserproject.eu). The HISER project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 642085.

References

[1]http://www.vlaanderen.be/nl/publicaties/detail/monitoringsysteem-duurzaam-oppervlaktedelfstoffenbeleid-jaarverslag-2013: MDO report (2014)

[2] http://www.baksteen.be/UserFiles/Image/downloads/jaarverslag-rapportannuel-2013.pdf: BBF year report (2014)

[3]http://ec.europa.eu/environment/eussd/pdf/footprint/PEF%20methodology%20final%20dr aft.pdf: PEF Guide (2013)

[4]http://www.ovam.be/sites/default/files/atoms/files/Environmental%20profile%20of%20bu ildig%20elements.pdfM: MMG impact assessment (2013)